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1.
Environ Monit Assess ; 195(3): 411, 2023 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-36807700

RESUMO

There is heightening concern regarding heavy metals environmental pollution requiring renewed global attention because of their bioaccumulation and toxicity at varying levels. The concern is most important in the highly migratory Eidolon helvum (E. helvum) that is very common and traverses wide geographical areas within the sub-Saharan Africa. The present study aimed to evaluate levels of cadmium (Cd), lead (Pb), and zinc (Zn) bioaccumulation in 24 E. helvum of both sexes from Nigeria to assess their indirect health risks to the human consumers of the bats in addition to their direct bioaccumulation and toxic damages in the bats themselves based on standard procedures. Lead, Zn, and Cd bioaccumulation concentrations were 2.83 ± 0.35, 0.42 ± 0.03, and 0.05 ± 0.01 mg/kg, respectively, with significant (p < 0.05) Pb bioaccumulation compared to either Cd or Zn in the affected bats. However, only Pb (markedly) and Cd (marginally) bioaccumulated above small mammals' critical threshold levels as there are no existing established threshold levels for bats. Sex played no major role in their bioaccumulation levels. The bioaccumulation levels posed no life-long non-carcinogenic nor carcinogenic risks to the human consumers of the bats at detected concentrations. The observed lungs, liver, and kidney histopathological changes suggested the possible direct effects of the metals in the bats. Nevertheless, other anthropogenic factors might be responsible as no significant (p > 0.05) correlation existed between cellular changes and the bioaccumulation levels. The presence of the heavy metals and their bioaccumulations above critical threshold levels suggested some levels of environmental contamination and pollution, which might have direct and indirect health implications to the bats and their human consumers.


Assuntos
Quirópteros , Metais Pesados , Animais , Humanos , Nigéria , Monitoramento Ambiental , Cádmio , Chumbo , Zinco , Medição de Risco
2.
Emerg Infect Dis ; 26(9): 2205-2209, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32818404

RESUMO

After the 2017 Ebola virus (EBOV) outbreak in Likati, a district in northern Democratic Republic of the Congo, we sampled small mammals from the location where the primary case-patient presumably acquired the infection. None tested positive for EBOV RNA or antibodies against EBOV, highlighting the ongoing challenge in detecting animal reservoirs for EBOV.


Assuntos
Ebolavirus , Doença pelo Vírus Ebola , Animais , Animais Selvagens , República Democrática do Congo/epidemiologia , Surtos de Doenças , Ebolavirus/genética , Doença pelo Vírus Ebola/epidemiologia , Humanos
3.
Emerg Infect Dis ; 24(12): 2228-2240, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30307845

RESUMO

To clarify the role of bats in the ecology of Ebola viruses, we assessed the prevalence of Ebola virus antibodies in a large-scale sample of bats collected during 2015-2017 from countries in Africa that have had previous Ebola outbreaks (Guinea, the Democratic Republic of the Congo) or are at high risk for outbreaks (Cameroon). We analyzed 4,022 blood samples of bats from >12 frugivorous and 27 insectivorous species; 2-37 (0.05%-0.92%) bats were seropositive for Zaire and 0-30 (0%-0.75%) bats for Sudan Ebola viruses. We observed Ebola virus antibodies in 1 insectivorous bat genus and 6 frugivorous bat species. Certain bat species widespread across Africa had serologic evidence of Zaire and Sudan Ebola viruses. No viral RNA was detected in the subset of samples tested (n = 665). Ongoing surveillance of bats and other potential animal reservoirs are required to predict and prepare for future outbreaks.


Assuntos
Doenças dos Animais/epidemiologia , Doenças dos Animais/virologia , Quirópteros/virologia , Ebolavirus , Doença pelo Vírus Ebola/veterinária , Doenças dos Animais/história , Doenças dos Animais/imunologia , Animais , Anticorpos Antivirais , Camarões/epidemiologia , República Democrática do Congo/epidemiologia , Surtos de Doenças , Ebolavirus/classificação , Ebolavirus/genética , Ebolavirus/imunologia , Geografia Médica , Guiné/epidemiologia , História do Século XXI , Vigilância em Saúde Pública , Estudos Soroepidemiológicos
4.
J Zoo Wildl Med ; 48(4): 1247-1249, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29297804

RESUMO

Carbaryl was the first carbamate insecticide produced and remains the most widely used due to its perceived low level of toxicity in nontarget species. This report describes the management and evaluation of a group of straw-colored fruit bats, Eidolon helvum, that were exposed to carbaryl. Cholinesterase activity of blood, retina, and brain was evaluated to further investigate whether carbaryl was the causative agent. Decreased whole blood and retinal cholinesterase activity coupled with the response to atropine suggests that the cause of the clinical signs in this bat colony was due to carbaryl exposure. Whole blood and retinal tissue may be the best samples for confirming carbamate exposure in this species.


Assuntos
Animais de Zoológico , Carbaril/intoxicação , Quirópteros , Inibidores da Colinesterase/intoxicação , Animais , Encéfalo/enzimologia , Carbaril/toxicidade , Inibidores da Colinesterase/toxicidade , Colinesterases/química , Colinesterases/metabolismo , Feminino , Masculino
5.
Biol Conserv ; 200: 131-139, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27499548

RESUMO

Animal behaviour, social structure and population dynamics affect community structure, interspecific interactions, and a species' resilience to harvesting. Building on new life history information for the straw-coloured fruit bat (Eidolon helvum) from multiple localities across Africa, we used survival analyses based on tooth-cementum annuli data to test alternative hypotheses relating to hunting pressure, demography and population connectivity. The estimated annual survival probability across Africa was high (≥ 0.64), but was greatest in colonies with the highest proportion of males. This difference in sex survival, along with age and sex capture biases and out-of-phase breeding across the species' distribution, leads us to hypothesize that E. helvum has a complex social structure. We found no evidence for additive mortality in heavily hunted populations, with most colonies having high survival with constant risk of mortality despite different hunting pressure. Given E. helvum's slow life history strategy, similar survival patterns and rate among colonies suggest that local movement and regional migration may compensate for local excess hunting, but these were also not clearly detected. Our study suggests that spatio-temporal data are necessary to appropriately assess the population dynamics and conservation status of this and other species with similar traits.

6.
J Zoo Wildl Med ; 47(1): 106-12, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27010270

RESUMO

Straw-colored fruit bats (Eidolon helvum) are an ecologically important species of megachiropteran bat that are common both in captivity and in the wild. This study attempts to determine reference intervals from a group of 45 captive individuals for a variety of hematologic and biochemistry parameters. Most of the values are similar to values previously seen in other pteropodid bat species. Differences included a lower than expected reference interval for the total white blood cell count, a wider reference interval for glucose, and a higher reference interval for 25-hydroxyvitamin D. Establishing reference intervals for hematologic and biochemistry analytes for bats that were maintained on the same diet and under the same husbandry parameters for several years will help in the future assessment of other bats maintained in a similar manner.


Assuntos
Contagem de Células Sanguíneas/veterinária , Quirópteros/sangue , Eletrólitos/sangue , Lipídeos/sangue , Animais , Animais de Zoológico , Sangue , Fígado/enzimologia , Valores de Referência
7.
Proc Biol Sci ; 281(1782): 20140018, 2014 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-24648227

RESUMO

When animals move, their tracks may be strongly influenced by the motion of air or water, and this may affect the speed, energetics and prospects of the journey. Flying organisms, such as bats, may thus benefit from modifying their flight in response to the wind vector. Yet, practical difficulties have so far limited the understanding of this response for free-ranging bats. We tracked nine straw-coloured fruit bats (Eidolon helvum) that flew 42.5 ± 17.5 km (mean ± s.d.) to and from their roost near Accra, Ghana. Following detailed atmospheric simulations, we found that bats compensated for wind drift, as predicted under constant winds, and decreased their airspeed in response to tailwind assistance such that their groundspeed remained nearly constant. In addition, bats increased their airspeed with increasing crosswind speed. Overall, bats modulated their airspeed in relation to wind speed at different wind directions in a manner predicted by a two-dimensional optimal movement model. We conclude that sophisticated behavioural mechanisms to minimize the cost of transport under various wind conditions have evolved in bats. The bats' response to the wind is similar to that reported for migratory birds and insects, suggesting convergent evolution of flight behaviours in volant organisms.


Assuntos
Quirópteros , Voo Animal , Vento , Animais , Modelos Biológicos
8.
Anat Histol Embryol ; 53(1): e13003, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37987196

RESUMO

The African straw-coloured fruit Bat, Eidolon helvum, is a Yinpterochiroptera bat that is of public health and ecological importance. This study investigated the light microscopic morphology, morphometry and histochemistry of the skin and its glands across the cheek, withers, croup, ventral abdomen, perianal region, wing membrane, intercrural membrane and foot pad of the species. Sweat glands were absent and hypodermis was observed only in the withers, croup and ventral abdomen. The croup had the highest density of hair follicles while the perianal region had the highest density of sebaceous gland acini. The thicknesses of the dermis and epidermis were significantly high in the withers and foot pad respectively. Hair follicles and sebaceous glands were absent in the wing membrane. The sebaceous glands had melanin pigmentation at the periphery and stained positive to Alcian Blue-periodic acid Schiff at the withers and ventral abdomen. Epidermal and dermal thicknesses reported in this study were generally higher than those of Yangochiroptera bats and the presence of sebaceous glands and hair follicles in the wing membrane were variable in different bat species. This study has provided baseline information on the light microscopic morphology and morphometry of the skin and its glands across the various body regions in the African straw-coloured fruit bat. This information would be helpful in the understanding, handling, skin disease treatment and management of the bat in captivity for biomedical research purposes.


Assuntos
Quirópteros , Crupe , Animais , Crupe/veterinária , Histocitoquímica/veterinária
9.
Int J Parasitol Parasites Wildl ; 21: 210-218, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37388298

RESUMO

We investigated ectoparasite diversity, interspecific infestation rates and host preference in roosting fruit bats, Eidolon helvum, from Bowen University, Southwest Nigeria. Fur of captured E. helvum were sampled monthly for ectoparasites from January 2021 to June 2022. We examined a total of 231 E. helvum and observed a significant female to male adult sex ratio (0.22:1); with 53.9% ectoparasitic infestation rate. We identified and enumerated the ectoparasite; and subjected its Cytochrome c oxidase subunit I (COI) gene to phylogenetic analysis with other nycteribiids. COI gene sequences obtained formed a distinct clade with other C. greeffi sequences. We recovered a total of 319 (149 female and 170 male) ectoparasites and observed a balanced C. greeffi female to male adult sex ratio of 0.88:1. Ectoparasitic sex distribution had no association with host sex and season. Prevalence was significantly higher during the wet season, but not between sexes of E. helvum. The intensity of infestation, 3.7 ± 0.4 individuals per fruit bat, was significantly higher during the wet season with a bimodal seasonal distribution. The strongly male-biased host adult sex ratio had no significant influence on C. greeffi metapopulation adult sex ratio.

10.
Front Public Health ; 11: 1283113, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38106901

RESUMO

Introduction: The Eidolon helvum fruit bat is one of the most widely distributed fruit bats in Africa and known to be a reservoir for several pathogenic viruses that can cause disease in animals and humans. To assess the risk of zoonotic spillover, we conducted a serological survey of 304 serum samples from E. helvum bats that were captured for human consumption in Makurdi, Nigeria. Methods: Using pseudotyped viruses, we screened 304 serum samples for neutralizing antibodies against viruses from the Coronaviridae, Filoviridae, Orthomyxoviridae and Paramyxoviridae families. Results: We report the presence of neutralizing antibodies against henipavirus lineage GH-M74a virus (odds ratio 6.23; p < 0.001), Nipah virus (odds ratio 4.04; p = 0.00031), bat influenza H17N10 virus (odds ratio 7.25; p < 0.001) and no significant association with Ebola virus (odds ratio 0.56; p = 0.375) in this bat cohort. Conclusion: The data suggest a potential risk of zoonotic spillover including the possible circulation of highly pathogenic viruses in E. helvum populations. These findings highlight the importance of maintaining sero-surveillance of E. helvum, and the necessity for further, more comprehensive investigations to monitor changes in virus prevalence, distribution over time, and across different geographic locations.


Assuntos
Quirópteros , Viroses , Animais , Humanos , Nigéria/epidemiologia , Zoonoses/epidemiologia , Anticorpos Neutralizantes
11.
Viruses ; 14(3)2022 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-35336967

RESUMO

The ecology of ebolaviruses is still poorly understood and the role of bats in outbreaks needs to be further clarified. Straw-colored fruit bats (Eidolon helvum) are the most common fruit bats in Africa and antibodies to ebolaviruses have been documented in this species. Between December 2018 and November 2019, samples were collected at approximately monthly intervals in roosting and feeding sites from 820 bats from an Eidolon helvum colony. Dried blood spots (DBS) were tested for antibodies to Zaire, Sudan, and Bundibugyo ebolaviruses. The proportion of samples reactive with GP antigens increased significantly with age from 0-9/220 (0-4.1%) in juveniles to 26-158/225 (11.6-70.2%) in immature adults and 10-225/372 (2.7-60.5%) in adult bats. Antibody responses were lower in lactating females. Viral RNA was not detected in 456 swab samples collected from 152 juvenile and 214 immature adult bats. Overall, our study shows that antibody levels increase in young bats suggesting that seroconversion to Ebola or related viruses occurs in older juvenile and immature adult bats. Multiple year monitoring would be needed to confirm this trend. Knowledge of the periods of the year with the highest risk of Ebolavirus circulation can guide the implementation of strategies to mitigate spill-over events.


Assuntos
Quirópteros , Ebolavirus , Animais , Anticorpos Antivirais , Camarões/epidemiologia , Ebolavirus/genética , Feminino , Lactação
12.
Folia Morphol (Warsz) ; 81(3): 715-722, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34308539

RESUMO

BACKGROUND: This work was designed to provide a morphologic, morphometric and histochemical description of the eye of the African straw-coloured fruit bat (Eidolon helvum). An explanation of the optical role of the choroidal papillae in the vision of megachiropteran bats was provided. MATERIALS AND METHODS: Enucleated eyes of captured fruit bats were measured and processed for light microscopy. RESULTS: Typical gross features of the mammalian eye including an anterior transparent cornea, posterior whitish sclera and a golden-brown iris surrounding a round pupil were observed in the eye. Presence of undulating retina typically found in megachiropterans was also seen. The ratio of mean corneal diameter to mean axial eye diameter was 0.58 ± 0.08. The histochemical investigation of the eye indicated the presence of mucins, proteoglycans, hyaluronic acid, glycogen and/or glycoproteins in the corneal, scleral, choroidal and retinal tissues. CONCLUSIONS: The presence of reflective materials of the tapetum lucidum on the undulating retina was shown to be a morphological adaptation for increased light sensitivity as each parabolic surface of the choroidal papillae served as a convex mirror, reflecting the light rays to the adjacent parabolic surface, thus sensitising photoreceptors in affected regions. This phenomenon thus empowers megachiropteran bats with improved scotopic visual capability and could explain why most of them are reliant on their vison without the need for echolocation.


Assuntos
Quirópteros , Papilas Gustativas , Animais , Quirópteros/anatomia & histologia , Retina
13.
Front Physiol ; 13: 910157, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36105294

RESUMO

The discovery of bats as reservoir hosts for a number of highly pathogenic zoonotic agents has led to an increasing interest of infectious disease research in experimental studies with bats. Therefore, we established breeding colonies of Rousettus aegyptiacus and Eidolon helvum fruit bats, which both have been identified as reservoir hosts for relevant zoonotic disease agents, such as Marburg virus and Lagos bat virus. Since 2013, individuals of both species have been recruited to the Friedrich-Loeffler-Institut (FLI) from zoological gardens in Europe, to where these species had been introduced from the wild several decades ago. The aviaries have been designed according to national recommendations published by the Federal Ministry of Agriculture. Under these conditions, both species have been reproducing for years. To better understand the physiology of these animals, and to generate baseline knowledge for infection experiments, we monitored the body core temperatures of R. aegyptiacus bats in the aviaries, and found a circadian variation between 34°C and 41.5°C. We also determined the hematological parameters of both species, and detected specific differences between both bat species. For values of clinical chemistry, no correlation to age or sex was observed. However, species-specific differences were detected since ALT, BUN and CREA were found to be significantly higher in R. aegyptiacus and GLU and TP were significantly higher in E. helvum bats. A higher hematocrit, hemoglobin and red blood cell level was observed in subadult R. aegyptiacus, with hemoglobin and red blood cells also being significantly increased compared to E. helvum. Lymphocytes were found to be the dominant white blood cells in both species and are higher in female E. helvum. Neutrophil granulocytes were significantly higher in E. helvum bats. This underlines the necessity to define baseline profiles for each bat species prior to their use in experimental challenge.

14.
Viruses ; 13(12)2021 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-34960647

RESUMO

Lagos bat lyssavirus (LBV) comprising four lineages (A, B, C and D) can potentially cause the fatal disease rabies. Although LBV-B was initially isolated in Nigeria in 1956, there is no information on LBV lineages circulating in Nigeria. This study was undertaken for the first time to measure the neutralizing antibodies against four lineages of LBVs in straw-colored fruit bats (Eidolon helvum) in Makurdi, Nigeria. Serum samples (n = 180) collected during two periods (November 2017-March 2018 and November 2018-March 2019) from terminally bled bats captured for human consumption were tested using a modified fluorescent antibody virus neutralization (mFAVN) assay. A high proportion of bat sera (74%) neutralized at least one lineage of LBV (with reciprocal titers from 9 to >420.89) and most of them neutralized LBV-A (63%), followed by LBV-D (49%), LBV-C (45%) and LBV-B (24%). The majority of positive sera (75%, n = 100) neutralized multiple LBV lineages while the remaining 25% (n = 33) neutralized only a single lineage, i.e., LBV-A (n = 23), LBV-D (n = 8) and LBV-C (n = 2). None exclusively neutralized LBV-B. The results suggest that exposure to LBV is common in E. helvum and that LBV-A (but not LBV-B) is likely to be circulating in this region of Nigeria.


Assuntos
Anticorpos Antivirais/sangue , Quirópteros/virologia , Lyssavirus/imunologia , Raiva/virologia , Infecções por Rhabdoviridae/virologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Feminino , Humanos , Lyssavirus/isolamento & purificação , Masculino , Pessoa de Meia-Idade , Nigéria/epidemiologia
15.
Anat Histol Embryol ; 50(2): 387-395, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33314240

RESUMO

The study investigated seasonal changes in the morphology of the seminal vesicles of Eidolon helvum in a typical African tropical environment. Seminal vesicles of forty-eight bats were examined during the early rainy, late rainy and peak dry seasons, using gross anatomical, histological and ultrastructural techniques. The interlobular connective tissue septa from the external capsule demarcated the glandular parenchyma into numerous lobules of tubulo-alveolar glands. A simple cuboidal epithelium of mono- or bi-nucleated cuboidal cells lined the glandular mucosa during the rainy season. This was replaced by a bistratified cuboidal epithelium, whose upper layer of cells showed evidence of degeneration, during the dry season. The PAS-positive secretory products appeared to be numerous during the rainy season, but few and clumped together during the dry season. The mean gross weight, interlobular septal thickness, acini diameter and epithelial height of the glands varied significantly with season. Ultrastructural features of the secretory cells during the rainy season showed well-developed cytoplasmic organelles, numerous electron lucid secretory vesicles and electron-dense granules. Secretory epithelial cells of the seminal vesicles are very active during the rainy season, while regeneration of degenerated epithelium in preparation for the next reproductive cycle occurs during the dry season.


Assuntos
Quirópteros , Animais , Células Epiteliais , Epitélio , Masculino , Estações do Ano , Glândulas Seminais
16.
One Health Outlook ; 2(1): 16, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32835170

RESUMO

BACKGROUND: Many ecologically important plants are pollinated or have their seeds dispersed by fruit bats, including the widely distributed African straw-colored fruit bats (Eidolon helvum). Their ability to fly long distances makes them essential for connecting plant populations across fragmented landscapes. While bats have been implicated as a reservoir of infectious diseases, their role in disease transmission to humans is not well understood. In this pilot study, we tracked E. helvum to shed light on their movement patterns in Tanzania and possible contact with other species. METHODS: Tracking devices were deployed on 25 bats captured in the Morogoro Municipal and Kilombero District area near the Udzungwa Mountains of Tanzania. Nightly flight patterns, areas corresponding to foraging bouts and feeding roosts, and new day roosts were determined from bat movement data and characterized according to their proximity to urban built-up and protected areas. Sites for additional environmental surveillance using camera traps were identified via tracking data to determine species coming in contact with fruits discarded by bats. RESULTS: Tracking data revealed variability between individual bat movements and a fidelity to foraging areas. Bats were tracked from one to six nights, with a mean cumulative nightly flight distance of 26.14 km (min: 0.33, max: 97.57) based on data from high-resolution GPS tags. While the majority of their foraging locations were in or near urban areas, bats also foraged in protected areas, of which the Udzungwa Mountains National Park was the most frequented. Camera traps in fruit orchards frequented by tracked bats showed the presence of multiple species of wildlife, with vervet monkeys (Chlorocebus pygerythrus) observed as directly handling and eating fruit discarded by bats. CONCLUSIONS: Because we observed multiple interactions of animals with fruits discarded by bats, specifically with vervet monkeys, the possibility of disease spillover risk exists via this indirect pathway. With flight distances of up to 97 km, however, the role of E. helvum in the seed dispersal of plants across both protected and urban built-up areas in Tanzania may be even more important, especially by helping connect increasingly fragmented landscapes during this Anthropocene epoch.

17.
J Morphol ; 281(11): 1446-1455, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32896971

RESUMO

We studied the morphological characteristics and seasonal changes of the bulbourethral gland of Eidolon helvum in a typical African tropical environment. Forty-eight bulbourethral glands were examined using gross anatomical, histological, histochemical, and ultrastructural techniques during the early rainy, late rainy, and peak dry seasons. The pear-shaped bilateral bulbourethral glands were located extra-abdominally in the inguinal region. Trabeculae from the capsule divided the parenchyma into numerous lobules of tubuloalveolar glandular acini. The mucosa was covered by a simple columnar epithelium consisting up of principal secretory cells, columnar dense cells and basal cells, which were progressively pronounced during the dry season. The principal cells contained eosinophilic granules, which were PAS positive while the dense cells did not show affinity for the stains. The mean gross weights, acini diameters, and epithelial heights were greater during the rainy season than the dry season. Ultrastructural evaluation showed that the cytoplasm of the principal cells contained well-developed Golgi complexes, rough endoplasmic reticulum, mitochondria, and secretory vesicles of varying electron densities and sizes. The secretory vesicles were numerous during the early rainy season, decreased during the late rainy season and were scanty during the peak dry season. The simple columnar epithelium observed during the rainy season was replaced by an undefined stratified epithelium during the dry season, and this was associated with cellular degenerations and regenerations. In conclusion, E. helvum has a typical mammalian bulbourethral gland, with a unique cell type, the dense cell whose functions are not well-understood. The gland exhibits cyclical seasonal variation in structure and secretory activity; being active during the early rainy season (breeding season), and showing the lowest activity during the dry season (non-breeding season). Glandular epithelial cell renewal occurs during the dry season in preparation for the next breeding season.


Assuntos
Glândulas Bulbouretrais/citologia , Glândulas Bulbouretrais/ultraestrutura , Quirópteros/anatomia & histologia , Estações do Ano , Animais , Glândulas Bulbouretrais/anatomia & histologia , Células Epiteliais/citologia , Células Epiteliais/ultraestrutura , Epitélio/ultraestrutura , Masculino , Reprodução/fisiologia
18.
Philos Trans R Soc Lond B Biol Sci ; 374(1782): 20190021, 2019 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-31401962

RESUMO

Pathogen circulation among reservoir hosts is a precondition for zoonotic spillover. Unlike the acute, high morbidity infections typical in spillover hosts, infected reservoir hosts often exhibit low morbidity and mortality. Although it has been proposed that reservoir host infections may be persistent with recurrent episodes of shedding, direct evidence is often lacking. We construct a generalized SEIR (susceptible, exposed, infectious, recovered) framework encompassing 46 sub-models representing the full range of possible transitions among those four states of infection and immunity. We then use likelihood-based methods to fit these models to nine years of longitudinal data on henipavirus serology from a captive colony of Eidolon helvum bats in Ghana. We find that reinfection is necessary to explain observed dynamics; that acute infectious periods may be very short (hours to days); that immunity, if present, lasts about 1-2 years; and that recurring latent infection is likely. Although quantitative inference is sensitive to assumptions about serology, qualitative predictions are robust. Our novel approach helps clarify mechanisms of viral persistence and circulation in wild bats, including estimated ranges for key parameters such as the basic reproduction number and the duration of the infectious period. Our results inform how future field-based and experimental work could differentiate the processes of viral recurrence and reinfection in reservoir hosts. This article is part of the theme issue 'Dynamic and integrative approaches to understanding pathogen spillover'.


Assuntos
Quirópteros , Reservatórios de Doenças/veterinária , Infecções por Henipavirus/veterinária , Henipavirus/fisiologia , Animais , Animais de Zoológico , Reservatórios de Doenças/virologia , Gana/epidemiologia , Infecções por Henipavirus/epidemiologia , Infecções por Henipavirus/transmissão , Infecções por Henipavirus/virologia , Prevalência , Estudos Soroepidemiológicos
19.
Front Microbiol ; 9: 162, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29487577

RESUMO

Bats are economically important animals and serve as food sources in some African regions. They can be colonized with the Staphylococcus aureus complex, which includes Staphylococcus schweitzeri and Staphylococcus argenteus. Fecal carriage of S. aureus complex in the straw-colored fruit bat (Eidolon helvum) has been described. However, data on their transmission and adaptation in animals and humans are limited. The aim of this study was to investigate the population structure of the S. aureus complex in E. helvum and to assess the geographical spread of S. aureus complex among other animals and humans. Fecal samples were collected from E. helvum in Obafemi Awolowo University, Ile-Ife, Nigeria. The isolates were characterized by antimicrobial susceptibility testing, spa typing and multilocus sequence typing (MLST). Isolates were screened for the presence of lukS/lukF-PV and the immune evasion cluster (scn, sak, chp) which is frequently found in isolates adapted to the human host. A Neighbor-Joining tree was constructed using the concatenated sequences of the seven MLST genes. A total of 250 fecal samples were collected and 53 isolates were included in the final analysis. They were identified as S. aureus (n = 28), S. schweitzeri (n = 11) and S. argenteus (n = 14). Only one S. aureus was resistant to penicillin and another isolate was intermediately susceptible to tetracycline. The scn, sak, and chp gene were not detected. Species-specific MLST clonal complexes (CC) were detected for S. aureus (CC1725), S. argenteus (CC3960, CC3961), and S. schweitzeri (CC2463). STs of S. schweitzeri from this study were similar to STs from bats in Nigeria (ST2464) and Gabon (ST1700) or from monkey in Côte d'Ivoire (ST2058, ST2072). This suggests host adaptation of certain clones to wildlife mammals with a wide geographical spread in Africa. In conclusion, there is evidence of fecal carriage of members of S. aureus complex in E. helvum. S. schweitzeri from bats in Nigeria are closely related to those from bats and monkeys in West and Central Africa suggesting a cross-species transmission and wide geographical distribution. The low antimicrobial resistance rates and the absence of the immune evasion cluster suggests a limited exposure of these isolates to humans.

20.
Zoonoses Public Health ; 64(8): 628-635, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28371424

RESUMO

A large population of straw-coloured fruit bats (Eidolon helvum) colonizes a prime area in the city of Accra where several public amenities are located. Although the colony is positive to several zoonotic viruses including the Ebola virus, there is limited information on the social dimensions of the existence of the bats. As a step towards effective response to health risk and conservation of the bats, this study assessed the knowledge and attitude of the community living around the bats and determined their level of environmental and public health consciousness. The community generally lacks interest in bat bushmeat consumption but had low knowledge and disease risk perception of the bats. Despite major campaigns during the recent Ebola outbreak in West Africa, elements of risky behaviour including disbelief and disregard for some preventive measures and lack of interest in post-bat exposure prophylaxis were recorded among a limited proportion of the community. There was the need to focus public health education on the community and possibly others that may have E. helvum colonies in West Africa.


Assuntos
Quirópteros/virologia , Ebolavirus/isolamento & purificação , Conhecimentos, Atitudes e Prática em Saúde , Doença pelo Vírus Ebola/epidemiologia , Doença pelo Vírus Ebola/prevenção & controle , Adolescente , Adulto , Animais , Criança , Coleta de Dados , Surtos de Doenças , Feminino , Gana/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Percepção , Adulto Jovem
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